[PATCH 1/2] cxl: Deprecate driver

[Andrew Donnellan <ajd@linux.ibm.com>]

The cxl driver is no longer actively maintained and we intend to remove it
in a future kernel release.

cxl has received minimal maintenance for several years, and is not
supported on the Power10 processor. We aren't aware of any users who are
likely to be using recent kernels.

Change its MAINTAINERS status to obsolete, update the sysfs ABI
documentation accordingly, add a warning message on device probe, change
the Kconfig options to label it as deprecated, and don't build it by
default.

Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
---
 Documentation/ABI/{testing => obsolete}/sysfs-class-cxl | 3 +++
 MAINTAINERS                                             | 4 ++--
 drivers/misc/cxl/Kconfig                                | 6 ++++--
 drivers/misc/cxl/of.c                                   | 2 ++
 drivers/misc/cxl/pci.c                                  | 2 ++
 5 files changed, 13 insertions(+), 4 deletions(-)
 rename Documentation/ABI/{testing => obsolete}/sysfs-class-cxl (99%)

diff --git a/Documentation/ABI/testing/sysfs-class-cxl b/Documentation/ABI/obsolete/sysfs-class-cxl
similarity index 99%
rename from Documentation/ABI/testing/sysfs-class-cxl
rename to Documentation/ABI/obsolete/sysfs-class-cxl
index cfc48a87706b..8cba1b626985 100644
--- a/Documentation/ABI/testing/sysfs-class-cxl
+++ b/Documentation/ABI/obsolete/sysfs-class-cxl
@@ -1,3 +1,6 @@
+The cxl driver is no longer maintained, and will be removed from the kernel in
+the near future.
+
 Please note that attributes that are shared between devices are stored in
 the directory pointed to by the symlink device/.
 For example, the real path of the attribute /sys/class/cxl/afu0.0s/irqs_max is
diff --git a/MAINTAINERS b/MAINTAINERS
index 17daa9ee9384..1737a8ff4f2b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6228,8 +6228,8 @@ CXL (IBM Coherent Accelerator Processor Interface CAPI) DRIVER
 M:	Frederic Barrat <fbarrat@linux.ibm.com>
 M:	Andrew Donnellan <ajd@linux.ibm.com>
 L:	linuxppc-dev@lists.ozlabs.org
-S:	Supported
-F:	Documentation/ABI/testing/sysfs-class-cxl
+S:	Obsolete
+F:	Documentation/ABI/obsolete/sysfs-class-cxl
 F:	Documentation/arch/powerpc/cxl.rst
 F:	arch/powerpc/platforms/powernv/pci-cxl.c
 F:	drivers/misc/cxl/
diff --git a/drivers/misc/cxl/Kconfig b/drivers/misc/cxl/Kconfig
index 5efc4151bf58..15307f5e4307 100644
--- a/drivers/misc/cxl/Kconfig
+++ b/drivers/misc/cxl/Kconfig
@@ -9,11 +9,13 @@ config CXL_BASE
 	select PPC_64S_HASH_MMU
 
 config CXL
-	tristate "Support for IBM Coherent Accelerators (CXL)"
+	tristate "Support for IBM Coherent Accelerators (CXL) (DEPRECATED)"
 	depends on PPC_POWERNV && PCI_MSI && EEH
 	select CXL_BASE
-	default m
 	help
+	  The cxl driver is deprecated and will be removed in a future
+	  kernel release.
+
 	  Select this option to enable driver support for IBM Coherent
 	  Accelerators (CXL).  CXL is otherwise known as Coherent Accelerator
 	  Processor Interface (CAPI).  CAPI allows accelerators in FPGAs to be
diff --git a/drivers/misc/cxl/of.c b/drivers/misc/cxl/of.c
index cf6bd8a43056..e26ee85279fa 100644
--- a/drivers/misc/cxl/of.c
+++ b/drivers/misc/cxl/of.c
@@ -295,6 +295,8 @@ int cxl_of_probe(struct platform_device *pdev)
 	int ret;
 	int slice = 0, slice_ok = 0;
 
+	dev_err_once(&pdev->dev, "DEPRECATION: cxl is deprecated and will be removed in a future kernel release\n");
+
 	pr_devel("in %s\n", __func__);
 
 	np = pdev->dev.of_node;
diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
index 3d52f9b92d0d..92bf7c5c7b35 100644
--- a/drivers/misc/cxl/pci.c
+++ b/drivers/misc/cxl/pci.c
@@ -1726,6 +1726,8 @@ static int cxl_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	int slice;
 	int rc;
 
+	dev_err_once(&dev->dev, "DEPRECATED: cxl is deprecated and will be removed in a future kernel release\n");
+
 	if (cxl_pci_is_vphb_device(dev)) {
 		dev_dbg(&dev->dev, "cxl_init_adapter: Ignoring cxl vphb device\n");
 		return -ENODEV;
-- 
2.47.1